Alternate action mechanism



a mu- May 17, 1955 R. w. PASHBY ALTERNATE ACTION MECHANISM Filed March15, 1954 INVENTOR.

ROBERT W. PASHBY ATTORNEY United States Patent U ALTERNATE ACTIONMECHANISM Robert W. Pashby, Freeport, Ill., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn, a corporation ofDelaware Application March 15, 1954, Serial No. 416,181

6 Claims. (Cl. 74-100) This invention is directed to a mechanism that isadapted to alternately shift a driven member between two positions onsuccessive operations of a driving member. The disclosed device isparticularly adapted for throwing a switch between two operativepositions on successive similar movements of a plunger.

An object of the invention is to provide an alternate action mechanismin which a high proportion of the total movement of the actuating memberis utilized in actually moving the alternating member.

Another object is to provide an alternate action mechanism whichrequires less force to effect its operation than in other known similardevice.

A further object is to provide an alternate action mechanism comprisingfew readily fabricated parts.

Other objects will be apparent from the following specification andclaims, and from the drawing in which:

Figure l is an elevation, partly in section, of an electric switchincorporating an embodiment of the invention,

Figure 2 is a plan view of a section of the switch case showing theswitch mechanism per se,

Figure 3 is a fragmentary elevation of the alternate action mechanism asseen from the left in Figure l, and

Figure 4 is a fragmentary elevation viewed as in Figure 1 but with theparts in a different operative position.

The disclosed embodiment of the invention is incorporated in analternate action electric switch suitable for mounting in a wall box formanual operation.

A frame or case of insulating material in the form of a box is made upof a top section 11 which has end walls 12 and 13 formed integrallytherewith, and a bottom section 14 which has integral side walls 15 and16. A pair of mounting ears 17 are formed in the end walls 12 and 13.

A switch blade 20 is secured at its right-hand end to an anchor plate 21which is carried in the bottom section 14 of the case 10. A terminal 22formed on an extension of the plate 21 is provided with a screw locatedon the outside of the case. The left-hand end of the blade 20 carriesmovable contacts 23 and 24 which cooperate with stationary contacts 25and 26 respectively. Contacts 25 and 26 are carried by terminal strips27 and 28 which are provided with screws located on the outside of thecase. The blade 26 comprises a pair of tension strips 200 disposed oneither side of a compression strip 20!), the right-hand end of whichrests in a groove in an alternator 30. The alternator 30 is pivotallymounted in the case 10 on a bearing provided by an edge of the blade 26.Alternator 39 is shaped to provide surfaces 31 and 32 that cooperatewith the upper surface of the blade 20 and the lower surface of anchorplate 21 to limit oscillatory movement. Pivotal movement of thealternator moves the right-hand end of the compression strip 20b acrossthe center line of the tension strips 20a to move the movable contacts23 and 24 with respect to the stationary contacts 25 and 26. The caseand switch structure as outlined above is similar to that disclosed inthe appli- 2,708,371 Patented May 17, 1955 ice cation of A. R. KochSerial No. 204,610 filed January 5, 1951, now Patent No. 2,684,418, towhich reference is made for a more detailed description.

A pair of lateral extensions on the alternator 30 are formed to provideabutment surfaces 35 and 36 which are symmetrically disposed withrespect to a plane through the pivotal axis and are equidistant from theaxis. In this embodiment of the invention the abutment surfaces 35 and36 are flat and lie in a common plane. The alternator 36 also has anextension 39 normal to the abutment surfaces 35 and 36, a notch 40 beingprovided at the upper extremity to receive the lower end of an expansionhair-pin spring 42. The upper end of the spring 42 pivotally engages anedge 43a of an actuator 43 which has an upper edge 43b pivotallyengaging a hearing portion 45a of an operating member 45. An inwardlyextending rim 11a on section 11 of case 10 cooperates with a shoulder45b on the periphery of the member 45 to limit outward movement thereof.Inward movement of the member 45 is limited by engagement of the bearingportion 45a with a shoulder 14a on the case section 14 as shown inFigure 4. While inward movement of the member 45 as shown in Figure 4 isaccomplished by translation of the member 45, operation of the devicemay also be accomplished by depressing one end of the member 45, inwhich case the shoulder 4511 at one end of member 45 may remain inengagement with the cooperating rim 11a and serve as a pivot for theremaining portions of the member 45. ln this case the bearing portion451: will describe an are on inward movement, but such motion willapproximate straight line movement of the bearing portion 45a toward thepivot of the alternator 30 and no change will result in the operation ofthe device as will be described hereinafter.

The actuator 43 is provided with an arm 43c having an abutment surfaceat its lower end adapted to engage abutment surface 35 of alternator 30.Likewise an arm 43d has an abutment surface at its lower extremityadapted to engage the abutment surface 36 of the altermeter 30. Each ofthe arms 43c and 43d has a portion adapted to engage a lateral surfaceof the extension 39 of the alternator 30 to limit pivotal movement ofthe actuator 43 in the bearing 45a with respect to the alternator 39. Asseen in Figure 1 the spring 42 is applying a force to the actuator 43having a moment tending to pivotally move the actuator 43 in acounterclockwise direction. Such movement is prevented by the engagementof the arm 430 with the extension 39. When the member 45 is depressed,the arm 430 will be guided by the extension 39 so that the arm 43d willengage the abutment surface 36 on the alternator 30. Continued downwardmovement of the member 43 will cause the arm 43d to move the alternator30 in a clockwise direction to the position shown in Figure 4. It willbe noted in Figure 4 that the extension 39 has moved the lower end ofthe hairin spring 42 to a position in which the spring now exerts aclockwise moment on the actuator 43. When the member 45 is allowed tomove outwardly the actuator 43 will be moved in a clockwise directionutnil the arm 43d engages the lateral surface of the extension 39 of thealternator 30. The spring 42, in addition to properly positioning theactuator 43, exerts a force biasing the member 45 outwardly whenoperating force is removed. Also, the spring 42 exerts a force tendingto maintain the alternator 39 in the position to which it has beenmoved. While the disclosed embodiment of the invention incorporates asnap switch moved by the alternator 30 and therefore the switch itselfexerts a force tending to hold the alternator in actuated position, thenovel features of the invention may be utilized with a switch of thetype that does no go through a position of unstable equilibrium.

When the member 45 is raised from the position shown in Figure 4 theactuator 43 will assume a position in which the arm 430 is immediatelyabove the abutment surface 35 on the actuator 3%) so that downward movement of the member 45 will cause return of the alternator 30 to theposition shown'in Figure 1. An advantage of the disclosed embodiment ofthe invention over known types of alternate ac ion mechanisms is thatwhen the member 45 and the actuator 43 are in retracted position onlyenough clearance need be provided between the lower surface of the armsand the abutment surface of the alternator to assure pivotal movement ofthe actuator to the proper position. Hence, inward movement of themember 45 is accompanied almost immediately by pivotal movement of thealternator. The movement of the member 45 is available almost in itsentirety for movement of the alternator and hence the device may bedesigned to operate with lower operating force. Likewise, the action ismore pleasing in that the required force does not rise abruptly at'apoint substantially midway in the movement of the operating member. Itwill be noted that the mechanism comprises a very few number of partswhich contributes to reliability and low manufacturing cost.

Numerous changes could be made in the configuration and disposition ofthe operative parts of the mechanism without departing from the spiritof the invention, the scope of which is to be limited only by theappended claims.

I claim:

1. An alternate action mechanism comprising, a frame, an alternatorpivoted in said frame, cooperating stops on said alternator and saidframe limiting the range of oscillatory movement of said alternator,said alternator having a pair of abutment surfaces symmetrion saidalternator selectively on alternate movements of said member toward thepivotal axis of said alternator, and a spring interconnecting saidactuator and said alternator, and movable through a condition of maximumstress on movement of said member to shift said alternator through itsrange of movement.

2. An alternate action mechanism comprising, a frame,

an alternator pivoted insaid frame, cooperating stops on said alternatorand said frame limiting the range of oscillatory movement of saidalternator, said alternator having a pair of abutment surfacessymmetrically disposed with respect to a plane in said alternatorthrough the pivotal axis, an actuator having a portion movable towardand away from the pivotal axis of said alternator on a line whichbisects the angle swept by said plane, a pair of arms on said actuatoreach adapted to engage one of the abutment surfaces of said alternatorand to drive said alternator in opposite directions on alternate inwardmovements of said actuator, cooperating pairs of guiding sur faces onsaid alternator and said actuator for selectively positioning each ofsaid arms to engage the cooperating abutment surface on said alternatorand a spring interconnecting said actuator and said alternator andmovable through a condition of maximurn'stress intermediate the range ofmovement of said alternator, said spring in conjunction with a pair ofguiding surfaces causing said actuator on outward movement to assume aposition that will causecngagement of an arm of said actuator with anabutment surface of said alternator on the next succeeding inwardmovement of said actuator.

3. An alternate action mechanism comprising, a frame, an alternatorpivoted in said frame, cooperating stops Kit on said alternator and saidframe limiting the range of oscillatory movement of said alternator,said alternator having a pair of abutment surfaces symmetricallydisposed with respect to a plane in said alternator through the pivotalaxis, an actuator having a portion movable toward and away from thepivotal axis of said alternator on a line which bisects the angle sweptby said plane, a pair of driving surfaces on said actuator each adaptedto engage one of the abutment surfaces of said alternator and to movesaid alternator in opposite directions on alternate inward movements ofsaid actuator, guiding surfaces on said alternator and said actuator toalign a driving surface of said actuator with the cooperating abutmentsurface of said alternator during inward movement of said actuator, anda spring acting between said actuator an said alternator connected toreverse the direction of lateral force on said alternator on eachactuation of the mechanism.

4. An alternate action mechanism comprising, a frame, an alternatorpivoted in said frame, said alternator having a pair of abutmentsurfaces symmetrically disposed thereon, a member carried in said frameand having a bearing portion movable toward and away from the axis ofsaid alternator, an actuator pivoted in the bearing portion of saidmember and having two driving surfaces each adapted to engage one of theabutment surfaces of said alternator upon alternate inward movement ofsaid member, cooperating guiding surfaces on said alternator and on saidactuator limiting pivotal movement of said actuator in each direction toa position relative to said alternator in which a driving surfaceengages an abutment surface, and spring means acting between saidalternator and said actuator biasing said member away from the axis ofsaid alternator and biasing said actuator pivotally to a limitingposition.

5. An alternate action mechanism comprising, a frame, an alternatorpivoted in said frame, cooperating stops on said alternator and saidframe limiting the range of oscillatory movement of said alternator,said alternator having a pair of abutment surfaces symmetricallydisposed with respect to a plane in said alternator through its pivotalaxis, a member carried in said frame and having a bearing portionmovable in a line that bisects the angle swept by the plane in saidalternator, cooperating stops on said member and said frame limitingoutward movement of said member, an actuator pivoted of spaced drivingsurfaces :each adapted to engage one of the abutment surfaces of saidalternator on inward movement of said member to move said alternator inone direction, cooperating guiding surfaces on. said altermater and saidactuator to align cooperating driving and abutment surfaces duringinward movement of said member, and a spring acting between saidalternator and said actuator biasing said alternator into engagementwith a stop on said frame, biasing said actuator pivotally to acorresponding guided position and biasing said memher into engagementwith the cooperating stop on said frame.

7 6. An alternate action mechanism comprising, a frame, an alternatorpivoted in said frame, cooperating stops on said alternator and saidframe limiting the range of oscillatory movement of said alternator,said alternator having a pair of spaced abutment surfaces symmetricallydisposed with respect to a plane in said alternator through its pivotalaxis, a member carried in said frame and having a bearing portionmovable in a line that bisects the angle swept by the plane in saidalternator, cooperating stops on said member and said frame limitingoutward movement of said member, an actuator pivoted in the bearingportion of said member and having a pair of spaced :riving portions eachadapted to engage one of the abutment surfaces of said alternator onalternate inward movements of said member, said alternator having anextension located between said driving portions #3 member, said springbiasing said alternator to engage a stop on said frame, biasing saidactuator pivotally to engage the extension on said alternator, andbiasing said member outwardly to engage the stop on said frame.

No references cited.

